Robotic finger and hand

ABSTRACT

A robotic finger is provided. The robotic finger includes a first member that has a plurality of rigid sections that are rotatably connected end-to-end through respective first joints. The robotic finger also includes a second member that has a plurality of flexible sections that are connected end-to-end at respective second joints. The robotic finger also includes a plurality of linkages connecting the first member and the second member so as to align the plurality of flexible sections with the plurality of rigid sections side-by-side, and a respective linkage connects a respective first joint of the first member to a respective second joint of the second member. The robotic finger further includes a fingertip section that connects a distal end the first member to a distal end of the second member.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of co-owned U.S. patent applicationSer. No. 14/929,768 filed Nov. 2, 2015, which is incorporated byreference herein in its entirety for all purposes.

BACKGROUND

As technology advances, various types of robotic devices are beingcreated for performing a variety of functions that may assist users.Robotic devices may be used for applications involving materialhandling, transportation, welding, assembly, and dispensing, amongothers. Over time, the manner in which these robotic systems operate isbecoming more intelligent, efficient, and intuitive. As robotic systemsbecome increasingly prevalent in numerous aspects of modern life, it isdesirable for robotic systems to be efficient. Therefore, a demand forefficient robotic systems has helped open up a field of innovation inactuators, movement, sensing techniques, as well as component design andassembly.

Robotic devices, such as robotic legs and arms, may include variouscomponents or attachments that are designed to interact with theenvironment. Such components may include robotic feet and hands, whichmay include additional components that can be used to support,stabilize, grip, and otherwise allow a robotic device to effectivelycarry out one or more actions.

In particular, robotic arms may include one or more “end effectors” thatinteract with the environment. For example, end effectors may beimpactive (such as a claw), ingressive (such as a pin or needle),astrictive (such as a vacuum or suction element) or contigutive(requiring contact for adhesion, such as glue).

SUMMARY

The present application discloses implementations that relate to arobotic finger and a robotic hand. In one example, the presentapplication describes a robotic finger. The robotic finger includes afirst member having a plurality of rigid sections that are rotatablyconnected end-to-end through respective first joints. The robotic fingeralso includes a second member having a plurality of flexible sectionsthat are connected end-to-end at respective second joints. The roboticfinger further includes a plurality of linkages connecting the firstmember and the second member so as to align the plurality of flexiblesections with the plurality of rigid sections side-by-side. Eachrespective linkage connects a respective first joint of the first memberto a respective second joint of the second member. The robotic fingeryet further includes a fingertip section that connects a distal end thefirst member to a distal end of the second member.

In some implementations, the robotic finger further includes a clutchconnected to a proximal end of the first member and a proximal end ofthe second member. The clutch has a groove or surface with a detent. Therobotic finger also includes a coupling connected to the clutch. Thecoupling maintains a linear relationship with the clutch when the fingeris in a state of normal operation, and allows the clutch and coupling torotate out of the linear relationship when a force applied to a side ofthe robotic finger is more than a threshold force.

In another example, a robotic hand includes a palm housing defining acavity. The robotic hand also includes a plurality of hydraulicactuators positioned in cavity. The robotic hand further includes aplurality of robotic fingers coupled to the hydraulic actuators. Eachrobotic finger of the robotic hand includes a first member having aplurality of rigid sections that are rotatably connected end-to-endthrough respective first joints. Each robotic finger also includes asecond member having a plurality of flexible sections that are connectedend-to-end at respective second joints. Each robotic finger furtherincludes a plurality of linkages connecting the first member and thesecond member so as to align the plurality of flexible sections with theplurality of rigid sections side-by-side. Each respective linkageconnects a respective first joint of the first member to a respectivesecond joint of the second member of each robotic finger. Each roboticfinger further includes a fingertip section that connects a distal endthe first member to a distal end of the second member.

In some implementations, each robotic finger further includes a clutchconnected to a proximal end of the first member and a proximal end ofthe second member. The clutch has a groove or surface with a detent.Each robotic finger also includes a coupling connected to the clutch.The coupling maintains a linear relationship with the clutch when thefinger is in a state of normal operation, and allows the clutch andcoupling to rotate out of the linear relationship when a force appliedto a side of the robotic finger is more than a threshold force.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the figures and the followingdetailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a configuration of a robotic system, according to anexample implementation.

FIG. 2 illustrates a perspective view of a quadruped robot, according toan example implementation.

FIG. 3 illustrates a perspective view of a biped robot, according to anexample implementation.

FIG. 4 illustrates an example robotic finger, according to an exampleimplementation.

FIG. 5 illustrates an example robotic hand, according to an exampleimplementation.

FIG. 6 illustrates an example robotic hand, according to an exampleimplementation.

FIG. 7 illustrates an example robotic hand having example roboticfingers, according to an example implementation.

FIG. 8 illustrates an example robotic hand having example roboticfingers, according to an example implementation.

FIG. 9 illustrates a flowchart, according to an example implementation.

FIG. 10A illustrates a cross-sectional view of an example clutch andcoupling, according to an example implementation.

FIG. 10B illustrates a bottom view of an example clutch, according to anexample implementation.

FIG. 11 illustrates a three-dimensional view of an example clutch andcoupling, according to an example implementation.

DETAILED DESCRIPTION

The following detailed description describes various features andfunctions of the disclosed devices, systems, and methods with referenceto the accompanying figures. The illustrative device, system, and methodembodiments described herein are not meant to be limiting. It should beunderstood that the words “exemplary,” “example,” and “illustrative,”are used herein to mean “serving as an example, instance, orillustration.” Any implementation, embodiment, or feature describedherein as “exemplary,” “example,” or “illustrative,” is not necessarilyto be construed as preferred or advantageous over other implementations,embodiments, or features. Further, the implementations and embodimentsdescribed herein are not meant to be limiting. It will be readilyunderstood that certain aspects of the disclosed devices, systems, andmethods can be arranged and combined in a wide variety of differentconfigurations, all of which are contemplated herein. Additionally, thefollowing detailed description describes various features and functionsof the disclosure with reference to the accompanying Figures. In theFigures, similar symbols typically identify similar components, unlesscontext dictates otherwise.

I. Overview

As noted above, robotic arms may include many different types of endeffectors. One common type of end effector is a gripper, which allows arobotic arm to grip objects. Many grippers include two or more fingersthat act to grasp an object in a pincer-like manner. Many of these typesof grippers include fingers with multiple sections that are controlledby multiple motors or actuators, similar to the structure of a humanfinger.

Example embodiments of robotic fingers described herein may include afirst member and a second member, making up a back side and a grippingside of the finger respectively. The first member may have a pluralityof rigid sections, rotatably connected end-to-end through respectivefirst joints. The rigid sections may be a hard plastic, and the jointsmay be pin joints, allowing the rigid sections to rotate. The secondmember may have a plurality of flexible sections, connected end-to-endat respective second joints. The second joints may be pin joints aswell, allowing the flexible sections to rotate at the connection points.The example robotic finger may also include a plurality of linkagesconnecting the first member and the second member. The linkages mayconnect respective first joints with respective second joints, so as toalign the plurality of flexible sections with the plurality of rigidsections side-by-side. In some examples, the number of rigid sectionsand flexible sections are the same, and the plurality of linkagesconnecting the respective first and second joints match up therespective sections of the first and second members. The example roboticfinger may also include a fingertip section that connects a distal endthe first member to a distal end of the second member. The fingertipsection may include a rubber tip, allowing the fingertip section toprovide the finger with added grip. The fingertip section may alsoinclude a fingernail to aid in gripping small objects.

The first and second members may include a plurality of rigid andflexible sections, respectively. In some examples, the first rigid andflexible sections connected to the fingertip section may be shorter thanthe second rigid and flexible sections respectively, which may beshorter than the third rigid and flexible sections, respectively. Theremay be a pattern in the lengths of the rigid and flexible sections suchthat the sections connected to the fingertip section are the shorts ofthe plurality, and each successive section farther from the fingertipsection is increasingly longer, such that the longest rigid and flexiblesections are located at the proximate end of the first and secondmembers, respectively (i.e., the end furthest from the fingertip).

In some examples, each flexible section of the plurality of flexiblesections may itself be made of a plurality of segments connected end toend. The plurality of segments may be an elastomer or flexible rubber,and arranged such that a string of segments are connected together tocreate each flexible section of the second member.

In other examples, the plurality of linkages connecting the first memberand the second member may be rotatably connected to the first and secondmembers. Thus, two of the plurality of rigid sections may be rotatablyconnected at a first respective joint, and at the same joint, rotatablyconnected to a linkage, while the other side of that linkage isrotatably connected to a second respective joint, that also connects twoof the plurality of flexible sections. In this way, the connectionsbetween the rigid sections, flexible sections, and linkages may be suchthat they allow for rotational movement, yet maintain a rigid structureunder certain circumstances.

In still other examples, the example robotic finger may include a clutchconnected to a proximal end of the first member and a proximal end ofthe second member. The clutch may have a groove or surface with adetent. The example robotic finger may also have a coupling connected tothe clutch. The coupling may have a member that fits into the groove,and allows the clutch to rotate with respect to the coupling. Thecoupling may maintain a linear relationship with the clutch when thefinger is in a state of normal operation, and may allow the clutch torotate out of the linear relationship when a force applied to a side ofthe robotic finger is more than a threshold force. In some examples, thecoupling may include a ball-nose spring plunger, such that when theclutch and coupling are in a linear relationship, the ball fits into thedetent. When a force more than the threshold force is applied to a sideof the finger, the ball may move out of the detent, and allow the clutchto rotate.

Some implementations described herein may include a robotic hand, whichmay include one or more robotic fingers. An example robotic hand mayinclude a palm housing that defines a cavity. The cavity may include aplurality of hydraulic actuators. The example robotic hand may alsoinclude a plurality of robotic fingers coupled to the plurality ofhydraulic actuators. The plurality of robotic fingers may take the formof the example robotic finger described herein.

II. Example Robotic Systems

FIG. 1 illustrates an example configuration of a robotic system that maybe used in connection with the implementations described herein. Therobotic system 100 may be configured to operate autonomously,semi-autonomously, and/or using directions provided by user(s). Therobotic system 100 may be implemented in various forms, such as a bipedrobot, quadruped robot, or some other arrangement. Furthermore, therobotic system 100 may also be referred to as a robot, robotic device,or mobile robot, among other designations.

As shown in FIG. 1, the robotic system 100 may include processor(s) 102,data storage 104, and controller(s) 108, which together may be part of acontrol system 118. The robotic system 100 may also include sensor(s)112, power source(s) 114, mechanical components 110, and electricalcomponents 116. Nonetheless, the robotic system 100 is shown forillustrative purposes, and may include more or fewer components. Thevarious components of robotic system 100 may be connected in any manner,including wired or wireless connections. Further, in some examples,components of the robotic system 100 may be distributed among multiplephysical entities rather than a single physical entity. Other exampleillustrations of robotic system 100 may exist as well.

Processor(s) 102 may operate as one or more general-purpose hardwareprocessors or special purpose hardware processors (e.g., digital signalprocessors, application specific integrated circuits, etc.). Theprocessor(s) 102 may be configured to execute computer-readable programinstructions 106, and manipulate data 107, both of which are stored inthe data storage 104. The processor(s) 102 may also directly orindirectly interact with other components of the robotic system 100,such as sensor(s) 112, power source(s) 114, mechanical components 110,and/or electrical components 116.

The data storage 104 may be one or more types of hardware memory. Forexample, the data storage 104 may include or take the form of one ormore computer-readable storage media that can be read or accessed byprocessor(s) 102. The one or more computer-readable storage media caninclude volatile and/or non-volatile storage components, such asoptical, magnetic, organic, or another type of memory or storage, whichcan be integrated in whole or in part with processor(s) 102. In someimplementations, the data storage 104 can be a single physical device.In other implementations, the data storage 104 can be implemented usingtwo or more physical devices, which may communicate with one another viawired or wireless communication. As noted previously, the data storage104 may include the computer-readable program instructions 106 and thedata 107. The data 107 may be any type of data, such as configurationdata, sensor data, and/or diagnostic data, among other possibilities.

The controller 108 may include one or more electrical circuits, units ofdigital logic, computer chips, and/or microprocessors that areconfigured to (perhaps among other tasks), interface between anycombination of the mechanical components 110, the sensor(s) 112, thepower source(s) 114, the electrical components 116, the control system118, and/or a user of the robotic system 100. In some implementations,the controller 108 may be a purpose-built embedded device for performingspecific operations with one or more subsystems of the robotic device100.

The control system 118 may monitor and physically change the operatingconditions of the robotic system 100. In doing so, the control system118 may serve as a link between portions of the robotic system 100, suchas between mechanical components 110 and/or electrical components 116.In some instances, the control system 118 may serve as an interfacebetween the robotic system 100 and another computing device. Further,the control system 118 may serve as an interface between the roboticsystem 100 and a user. The instance, the control system 118 may includevarious components for communicating with the robotic system 100,including a joystick, buttons, and/or ports, etc. The example interfacesand communications noted above may be implemented via a wired orwireless connection, or both. The control system 118 may perform otheroperations for the robotic system 100 as well.

During operation, the control system 118 may communicate with othersystems of the robotic system 100 via wired or wireless connections, andmay further be configured to communicate with one or more users of therobot. As one possible illustration, the control system 118 may receivean input (e.g., from a user or from another robot) indicating aninstruction to perform a particular gait in a particular direction, andat a particular speed. A gait is a pattern of movement of the limbs ofan animal, robot, or other mechanical structure.

Based on this input, the control system 118 may perform operations tocause the robotic device 100 to move according to the requested gait. Asanother illustration, a control system may receive an input indicatingan instruction to move to a particular geographical location. Inresponse, the control system 118 (perhaps with the assistance of othercomponents or systems) may determine a direction, speed, and/or gaitbased on the environment through which the robotic system 100 is movingen route to the geographical location.

Operations of the control system 118 may be carried out by theprocessor(s) 102. Alternatively, these operations may be carried out bythe controller 108, or a combination of the processor(s) 102 and thecontroller 108. In some implementations, the control system 118 maypartially or wholly reside on a device other than the robotic system100, and therefore may at least in part control the robotic system 100remotely.

Mechanical components 110 represent hardware of the robotic system 100that may enable the robotic system 100 to perform physical operations.As a few examples, the robotic system 100 may include physical memberssuch as leg(s), arm(s), wheel(s), hand(s), finger(s), and/or feet. Thephysical members or other parts of robotic system 100 may furtherinclude actuators arranged to move the physical members in relation toone another. The robotic system 100 may also include one or morestructured bodies for housing the control system 118 and/or othercomponents, and may further include other types of mechanicalcomponents. The particular mechanical components 110 used in a givenrobot may vary based on the design of the robot, and may also be basedon the operations and/or tasks the robot may be configured to perform.

In some examples, the mechanical components 110 may include one or moreremovable components. The robotic system 100 may be configured to addand/or remove such removable components, which may involve assistancefrom a user and/or another robot. For example, the robotic system 100may be configured with removable arms, hands, feet, and/or legs, so thatthese appendages can be replaced or changed as needed or desired. Insome implementations, the robotic system 100 may include one or moreremovable and/or replaceable battery units or sensors. Other types ofremovable components may be included within some implementations.

The robotic system 100 may include sensor(s) 112 arranged to senseaspects of the robotic system 100. The sensor(s) 112 may include one ormore force sensors, torque sensors, velocity sensors, accelerationsensors, position sensors, proximity sensors, motion sensors, locationsensors, load sensors, temperature sensors, touch sensors, depthsensors, ultrasonic range sensors, infrared sensors, object sensors,and/or cameras, among other possibilities. Within some examples, therobotic system 100 may be configured to receive sensor data from sensorsthat are physically separated from the robot (e.g., sensors that arepositioned on other robots or located within the environment in whichthe robot is operating).

The sensor(s) 112 may provide sensor data to the processor(s) 102(perhaps by way of data 107) to allow for interaction of the roboticsystem 100 with its environment, as well as monitoring of the operationof the robotic system 100. The sensor data may be used in evaluation ofvarious factors for activation, movement, and deactivation of mechanicalcomponents 110 and electrical components 116 by control system 118. Forexample, the sensor(s) 112 may capture data corresponding to the terrainof the environment or location of nearby objects, which may assist withenvironment recognition and navigation. In an example configuration,sensor(s) 112 may include RADAR (e.g., for long-range object detection,distance determination, and/or speed determination), LIDAR (e.g., forshort-range object detection, distance determination, and/or speeddetermination), SONAR (e.g., for underwater object detection, distancedetermination, and/or speed determination), VICON® (e.g., for motioncapture), one or more cameras (e.g., stereoscopic cameras for 3Dvision), a global positioning system (GPS) transceiver, and/or othersensors for capturing information of the environment in which therobotic system 100 is operating. The sensor(s) 112 may monitor theenvironment in real time, and detect obstacles, elements of the terrain,weather conditions, temperature, and/or other aspects of theenvironment.

Further, the robotic system 100 may include sensor(s) 112 configured toreceive information indicative of the state of the robotic system 100,including sensor(s) 112 that may monitor the state of the variouscomponents of the robotic system 100. The sensor(s) 112 may measureactivity of systems of the robotic system 100 and receive informationbased on the operation of the various features of the robotic system100, such the operation of extendable legs, arms, or other mechanicaland/or electrical features of the robotic system 100. The data providedby the sensor(s) 112 may enable the control system 118 to determineerrors in operation as well as monitor overall operation of componentsof the robotic system 100.

As an example, the robotic system 100 may use force sensors to measureload on various components of the robotic system 100. In someimplementations, the robotic system 100 may include one or more forcesensors on an arm, leg, hand, foot, or finger to measure the load on theactuators that move one or more members of the arm, leg, hand, foot, orfinger. As another example, the robotic system 100 may use one or moreposition sensors to sense the position of the actuators of the roboticsystem. For instance, such position sensors may sense states ofextension, retraction, or rotation of the actuators on arms, legs,hands, feet, or fingers.

As another example, the sensor(s) 112 may include one or more velocityand/or acceleration sensors. For instance, the sensor(s) 112 may includean inertial measurement unit (IMU). The IMU may sense velocity andacceleration in the world frame, with respect to the gravity vector. Thevelocity and acceleration sensed by the IMU may then be translated tothat of the robotic system 100 based on the location of the IMU in therobotic system 100 and the kinematics of the robotic system 100.

The robotic system 100 may include other types of sensors not explicateddiscussed herein. Additionally or alternatively, the robotic system mayuse particular sensors for purposes not enumerated herein.

The robotic system 100 may also include one or more power source(s) 114configured to supply power to various components of the robotic system100. Among other possible power systems, the robotic system 100 mayinclude a hydraulic system, electrical system, batteries, and/or othertypes of power systems. As an example illustration, the robotic system100 may include one or more batteries configured to provide charge tocomponents of the robotic system 100. Some of the mechanical components110 and/or electrical components 116 may each connect to a differentpower source, may be powered by the same power source, or be powered bymultiple power sources.

Any type of power source may be used to power the robotic system 100,such as electrical power or a gasoline engine. Additionally oralternatively, the robotic system 100 may include a hydraulic systemconfigured to provide power to the mechanical components 110 using fluidpower. Components of the robotic system 100 may operate based onhydraulic fluid being transmitted throughout the hydraulic system tovarious hydraulic motors and hydraulic cylinders, for example. Thehydraulic system may transfer hydraulic power by way of pressurizedhydraulic fluid through tubes, flexible hoses, or other links betweencomponents of the robotic system 100. The power source(s) 114 may chargeusing various types of charging, such as wired connections to an outsidepower source, wireless charging, combustion, or other examples.

The electrical components 116 may include various mechanisms capable ofprocessing, transferring, and/or providing electrical charge or electricsignals. Among possible examples, the electrical components 116 mayinclude electrical wires, circuitry, and/or wireless communicationtransmitters and receivers to enable operations of the robotic system100. The electrical components 116 may interwork with the mechanicalcomponents 110 to enable the robotic system 100 to perform variousoperations. The electrical components 116 may be configured to providepower from the power source(s) 114 to the various mechanical components110, for example. Further, the robotic system 100 may include electricmotors. Other examples of electrical components 116 may exist as well.

Although not shown in FIG. 1, the robotic system 100 may include a body,which may connect to or house appendages and components of the roboticsystem. As such, the structure of the body may vary within examples andmay further depend on particular operations that a given robot may havebeen designed to perform. For example, a robot developed to carry heavyloads may have a wide body that enables placement of the load.Similarly, a robot designed to reach high speeds may have a narrow,small body that does not have substantial weight. Further, the bodyand/or the other components may be developed using various types ofmaterials, such as metals or plastics. Within other examples, a robotmay have a body with a different structure or made of various types ofmaterials.

The body and/or the other components may include or carry the sensor(s)112. These sensors may be positioned in various locations on the roboticdevice 100, such as on the body and/or on one or more of the appendages,among other examples.

On its body, the robotic device 100 may carry a load, such as a type ofcargo that is to be transported. The load may also represent externalbatteries or other types of power sources (e.g., solar panels) that therobotic device 100 may utilize. Carrying the load represents one exampleuse for which the robotic device 100 may be configured, but the roboticdevice 100 may be configured to perform other operations as well.

As noted above, the robotic system 100 may include various types oflegs, arms, wheels, and so on. In general, the robotic system 100 may beconfigured with zero or more legs. An implementation of the roboticsystem with zero legs may include wheels, treads, or some other form oflocomotion. An implementation of the robotic system with two legs may bereferred to as a biped, and an implementation with four legs may bereferred as a quadruped. Implementations with six or eight legs are alsopossible. For purposes of illustration, biped and quadrupedimplementations of the robotic system 100 are described below.

FIG. 2 illustrates a quadruped robot 200, according to an exampleimplementation. Among other possible features, the robot 200 may beconfigured to perform some of the operations described herein. The robot200 includes a control system, and legs 204A, 204B, 204C, 204D connectedto a body 208. Each leg may include a respective foot 206A, 206B, 206C,206D that may contact a surface (e.g., a ground surface). Further, therobot 200 is illustrated with sensor(s) 210, and may be capable ofcarrying a load on the body 208. Within other examples, the robot 200may include more or fewer components, and thus may include componentsnot shown in FIG. 2. For example, in addition to legs 204A, 20BB, 204C,and 204D, quadruped robot 200 may include one or more arms, hands,and/or fingers, such as those described elsewhere in this disclosure.

The robot 200 may be a physical representation of the robotic system 100shown in FIG. 1, or may be based on other configurations. Thus, therobot 200 may include one or more of mechanical components 110,sensor(s) 112, power source(s) 114, electrical components 116, and/orcontrol system 118, among other possible components or systems.

The configuration, position, and/or structure of the legs 204A-204D(and/or various other arms, hands, and/or fingers) may vary in exampleimplementations. The legs 204A-204D enable the robot 200 to moverelative to its environment, and may be configured to operate inmultiple degrees of freedom to enable different techniques of travel. Inparticular, the legs 204A-204D may enable the robot 200 to travel atvarious speeds according to the mechanics set forth within differentgaits. The robot 200 may use one or more gaits to travel within anenvironment, which may involve selecting a gait based on speed, terrain,the need to maneuver, and/or energy efficiency.

Further, different types of robots may use different gaits due tovariations in design. Although some gaits may have specific names (e.g.,walk, trot, run, bound, gallop, etc.), the distinctions between gaitsmay overlap. The gaits may be classified based on footfall patterns—thelocations on a surface for the placement the feet 206A-206D. Similarly,gaits may also be classified based on ambulatory mechanics.

The body 208 of the robot 200 connects to the legs 204A-204D and mayhouse various components of the robot 200. For example, the body 208 mayinclude or carry sensor(s) 210. These sensors may be any of the sensorsdiscussed in the context of sensor(s) 112, such as a camera, LIDAR, oran infrared sensor. Further, the locations of sensor(s) 210 are notlimited to those illustrated in FIG. 2. Thus, sensor(s) 210 may bepositioned in various locations on the robot 200, such as on the body208 and/or on one or more of the legs 204A-204D, among other examples.

FIG. 3 illustrates a biped robot 300 according to another exampleimplementation. Similar to robot 200, the robot 300 may correspond tothe robotic system 100 shown in FIG. 1, and may be configured to performsome of the implementations described herein. Thus, like the robot 200,the robot 300 may include one or more of mechanical components 110,sensor(s) 112, power source(s) 114, electrical components 116, and/orcontrol system 118.

For example, the robot 300 may include legs 304 and 306 connected to abody 308. Each leg may consist of one or more members connected byjoints and configured to operate with various degrees of freedom withrespect to one another. Each leg may also include a respective foot 310and 312, which may contact a surface (e.g., the ground surface). Likethe robot 200, the legs 304 and 306 may enable the robot 300 to travelat various speeds according to the mechanics set forth within gaits. Therobot 300, however, may utilize different gaits from that of the robot200, due at least in part to the differences between biped and quadrupedcapabilities.

The robot 300 may also include arms 318 and 320. These arms mayfacilitate object manipulation, load carrying, and/or balancing for therobot 300. Like legs 304 and 306, each arm may consist of one or moremembers connected by joints and configured to operate with variousdegrees of freedom with respect to one another. Each arm may alsoinclude a respective hand 322 and 324. The robot 300 may use hands 322and 324 to facilitate gripping, turning, pulling, and/or pushingobjects. The hands 322 and 324 may include various types of appendagesor attachments, such as fingers, grippers, welding tools, cutting tools,and so on. For instance, hands 322 and 324 may include respective setsof fingers 326 and 328. Fingers 326 and 328 may include one or morefingers such as those described below with reference to the variousother figures and embodiments.

The robot 300 may also include sensor(s) 314, corresponding to sensor(s)112, and configured to provide sensor data to its control system. Insome cases, the locations of these sensors may be chosen in order tosuggest an anthropomorphic structure of the robot 300. Thus, asillustrated in FIG. 3, the robot 300 may contain vision sensors (e.g.,cameras, infrared sensors, object sensors, range sensors, etc.) withinits head 316.

III. Example Robotic Finger

As noted above, the present disclosure includes implementations thatrelate to robotic fingers and/or robotic hands. FIG. 4 illustrates arobotic finger 400 according to an example implementation. Finger 400may be implemented as a mechanical component of system 100, quadrupedrobot 200, and/or biped robot 300. Although the components illustratedin FIG. 4 are shown with a certain orientation and/or design, it shouldbe understood that one or more components of robotic finger 400 may beremoved, added, and/or modified while remaining within the scope of thisdisclosure. Also, the orientation and combination of components may bechanged based on the desired implementation.

Robotic finger 400 may generally show a finger with a rigid dorsalstructure and a flexible ventral structure. The flexible ventralstructure may have a tread or grippable surface that runs the length ofthe robotic finger. Robotic finger 400 may include a first member 401and a second member 411. Robotic finger 400 may also include a pluralityof linkages 420A and 420B connecting first member 401 and second member411, and a fingertip section 430.

First member 401 may include a plurality of rigid sections 402A and402B. Each rigid section may be shaped in a cylindrical or rectangularprism shape. For instance, the plurality of rigid sections shown in FIG.4 each have a top end and a bottom end that are rounded, as well as aninside and an outside. The outside of the rigid sections may be rounded,as shown in FIG. 4.

The design of each rigid section may be similar, or may vary dependingon the desired implementation. Referring to the outside of the pluralityof rigid sections, in some examples there may be a slight curve (seeFIGS. 4-6, 8) while in other examples the outside of the plurality ofrigid sections may be generally straight (see FIG. 7). Various otherdesigns are possible as well. The specific design of the plurality ofrigid sections may allow for easier and/or less expensive manufacturing,and/or may provide increased performance such as stronger grip, reducedcomplexity, survivability/robustness, weight reduction, or various otherbenefits.

In some implementations, the plurality of rigid sections may have aspecific relationship to each other. For instance, where a first member401 includes two rigid sections, the first rigid section may beconnected to a fingertip section and may be shorter than the secondrigid section. In another example, where a first member includes threerigid sections, the first rigid section may be connected to a fingertipsection, and may be shorter than the second rigid section (i.e., amiddle section), which may be shorter than the third rigid section. Inthis way, the first member may have multiple rigid sections, where theshortest rigid section is connected to the fingertip section, and therigid sections become progressively longer the further they are from thefingertip.

In some implementations, each rigid section may have a cavity thatallows for rigid or flexible circuitry to be included. For example, theplurality of rigid sections may include one or more pressure,positional, or tactile sensors, which may provide a control system withinformation about the position, orientation, and grip strength of therobotic finger. The plurality of rigid section may provide increasedprotection for one or more included sensors or circuits as compared toflexible sections.

In some implementations, the plurality of rigid sections may be a hardplastic or metal. In other examples, composite materials or other typesof materials may be used.

First member 401 may also include a plurality of first joints 404A,404B, and 404C. First joints 404A, 404B, and 404C may be connected torigid sections 402A and 402B at their respective ends. For instance,rigid section 402A may include a bottom and a top, and may include firstjoint 404A at the bottom and first joint 404B at the top. Similarly,rigid section 402B may include a bottom and a top, and may include firstjoint 404B at the bottom and first joint 404C at the top. Rigid sections402A and 402B may thus be connected end to end via first joint 404B.

In some examples, first joints 404A, 404B and 404C may be pin joints.The first joints may allow rigid sections 402A and 402B to be rotatablyconnected, allowing the plurality of rigid sections to form a straightline, or to move out of line and form a bend or curve. In otherexamples, first joints 404A, 404B, and 404C may be pivot joints, rollingjoints, or circular joints. Other types of joints are possible as well.

Second member 411 of robotic finger 400 may include a plurality offlexible sections 412A and 412B. Each flexible section of the pluralityof flexible sections may be shaped in a cylindrical or rectangular prismshape. For instance, each of the plurality of flexible sections shown inFIG. 4 has a top end and a bottom end, as well as an inside and anoutside, and has an elongated shape. The top and bottom of each of theplurality of flexible sections may include respective second joints. Insome examples, the plurality of flexible section may be connectedend-to-end at respective second joints. The outside of the plurality offlexible sections may be configured to grip an object. As such, in someexamples the flexible section may be an elastomer, rubber, plastic, orover molded polyurethane. Each flexible section may be configured suchthat it deforms when pressure is applied, and returns to an initialstate when the pressure is removed. As such, no return spring or returnforce other than the structure of the flexible section may be needed toreturn the flexible section to an initial state.

The design of each flexible section may be the same, or may varydepending on the desired implementation. In some examples, each flexiblesection may be straight when in an initial state (see FIGS. 4-8) whilein other examples, each flexible section may be curved or bent. Variousother designs are possible as well. The specific design of the pluralityof flexible sections may allow for easier and/or less expensivemanufacturing, and/or may provide increased performance such as astronger grip, reduced complexity, reduced slippage of an object in thefinger's grasp, increased points of contact with an object, and/or otherbenefits.

In some implementations, the plurality of flexible sections may have aspecific relationship to each other. For instance, where a second member411 includes two flexible sections, the first flexible section may beconnected to a fingertip section and may be shorter than the secondflexible section. In another example, where a second member includesthree flexible sections, the first flexible section may be connected toa fingertip section, and may be shorter than the second flexible section(i.e., a middle section), which may be shorter than the third flexiblesection. In this way, the second member may have multiple flexiblesections, where the shortest flexible section is connected to thefingertip section, and the flexible sections become progressively longerthe further they are from the fingertip.

In some implementations, each flexible section may have a cavity thatallows for rigid or flexible circuitry to be included. For example, theplurality of flexible sections may include one or more pressure,positional, or tactile sensors, which may provide a control system withinformation about the position, orientation, and grip strength of therobotic finger. In other implementations, flexible circuitry may beincluded on an outside or gripping side of one or more flexible sectionsof the plurality of flexible sections.

In some implementations, the plurality of flexible sections may be madefrom elastomer, rubber, or another flexible material, such that eachflexible section may be able to deform from an initial state. In otherexamples, composite materials or other types of materials may be used.

In some examples, each of the plurality of flexible sections 412A and412B may have a design or structure that allows the flexible section tobend, twist, deform, curve, or otherwise change its shape. For instance,a flexible section may include an accordion design such that it canexpand and contract along an axis that connects the flexible sectionend-to-end with one or more other flexible sections. In other examples,a flexible section may include a plurality of segments. The plurality ofsegments may be shaped like teeth, and each segment may have one or morebend points. The plurality of segments may be connected end-to-end toform a flexible section. In some examples, the plurality of segments maybe rounded, and/or may be shaped to grip an object.

In some examples, the plurality of flexible sections and/or plurality ofsegments of a flexible section may be made of an elastomer, rubber,foam, or another material. The plurality of segments may be connectedend-to-end via a mid-point or central portion of each segment, and mayinclude a small gap between each segment such that plurality of segmentscombined into the flexible section can bend into a curved shaped whenpressure is applied to the flexible section. In some examples, theplurality of segments may be configured such that they bend into a curvewhen pressure is applied only along the plane including the finger. Assuch, the plurality of segments may maintain a linear relationship,and/or may not deform when a pressure applied to a side of the pluralityof segments. The plurality of segment may be configured to only bend ina single plane.

Second member 411 may also include a plurality of second joints 414A,414B, and 414C. Second joints 414A, 414B, and 414C may be connected toflexible sections 412A and 412B at their respective ends. For instance,flexible section 412A may include a bottom and a top, and may includesecond joint 414A at the bottom and second joint 414B at the top.Similarly, flexible section 412B may include a bottom and a top, and mayinclude second joint 414B at the bottom and first joint 414C at the top.Flexible sections 412A and 412B may thus be connected end to end viasecond joint 414B. In other embodiments, flexible sections 412A and 412Bmay be connected end-to-end independently from second joint 414B (i.e.,via a static joint forming a single flexible piece), and second joint414B may be connected to the single flexible piece at the point whereflexible section 412A connects to flexible section 412B (i.e., at thestatic joint).

In some examples, second joints 414A and 414B may be pin joints, asshown in FIG. 4. The second joints may allow flexible sections 412A and412B to be rotatably connected, allowing the plurality of flexiblesections to form a straight line or to move out of line and form a bendor curve. In other examples, second joints 414A and 414B may be pivotjoints or circular joints. Also shown in FIG. 4, second joint 414C mayinclude a static joint connecting flexible section 412B and fingertipsection 430, such that flexible section 412B does not rotate withrespect to fingertip section 430. Flexible section 412B and fingertipsection 430 may thus maintain a linear relationship. Other types ofjoints are possible as well.

Robotic finger 400 in FIG. 4 may also include a plurality of linkages420A and 420B. Linkages 420A and 420B may connect first member 401 tosecond member 411 so as to align the plurality of rigid sections withthe plurality of flexible sections side-by-side. The linkages may alignthe plurality of rigid sections with the plurality of flexible sectionssuch that a first respective rigid and flexible section are nearlyparallel to each other, and a second respective rigid and flexiblesection are nearly parallel to each other, as shown in FIG. 4 withreference to rigid sections 402A and 402B, and flexible sections 412Aand 412B. Each of the plurality of linkages may be rectangular in shape,and/or may have one or more bends, curves, notches, or other structuralcharacteristics. The plurality of linkages may be the same material asthe plurality of rigid sections (i.e., a hard plastic, metal, or othermaterial) or may be any other type of material.

In some implementations, linkages 420A and 420B may include respectivegripping sides and back sides, with joints on each side. The back sideof a respective linkage may include a respective first joint, and thegripping side of a respective linkage may include a respective secondjoint. Shown in FIG. 4, linkage 420A includes first joint 404A on theback side, and includes second joint 414A on the gripping side.Similarly, linkage 420B includes first joint 404B on the back side andsecond joint 414B on the gripping side. In this manner, the plurality oflinkages connect respective first and second joints of the first memberand second member, such that the plurality of rigid sections andflexible sections are aligned.

In some examples, the linkages may include pin joints, as shown in FIG.4. Pin joints may allow the linkages to by rotatably connected torespective rigid sections and flexible sections. In other examples, thelinkages may include static joints, rolling joints, or other types ofjoints. In still other examples, the linkages may include one type ofjoint on the gripping side, and another type of joint on the back side.

In some examples, the plurality of rigid sections and plurality offlexible sections may be aligned such that a first rigid section and afirst flexible section are both connected to a fingertip section of arobotic finger, forming a nearly parallel relationship. The relationshipbetween a respective rigid section and a respective flexible section mayalso form a generally trapezoidal shape, such that the top of a rigidsection and top of a flexible section is closer than the bottom of thesame rigid and flexible sections. A second rigid section and a secondflexible section, connected end-to-end with respective first rigidsection and flexible section, may also be generally parallel (or roughlytrapezoidal) to each other. The respective rigid sections and flexiblesections may be connected a plurality of linkages, such that theparallel (or roughly trapezoidal) relationship is maintained.

In some implementations, linkages in the plurality of linkages may be agiven length based on a relationship between the plurality of linkages.For instance, a first linkage connecting the rigid and flexible sectionsthat are connected to the fingertip section may be shorter than alinkage connecting the second rigid and flexible sections. As a result,a roughly trapezoidal alignment is formed by the plurality of rigidsections, plurality of flexible sections, and plurality of linkages.

In some implementations, the structure and orientation of the elementsof the robotic finger (plurality of linkages, rigid sections, flexiblesections, and fingertip section) is such that a stable initial state isformed, such as that shown in FIG. 4. This initial state may be anequilibrium, such that when the finger is forced out of the initialstate by an impacting force, removing the impacting force causes therobotic finger to return to the initial state without any additionalforce.

Robotic finger 400 in FIG. 4 may also include a fingertip section 430.Fingertip section 430 may be connected to a distal end of first member401 by a respective first joint 404C, and connected to a distal end ofsecond member 411 by a respective second joint 414C. Fingertip section430 may be rubber, or may be another material suited for gripping one ormore objects. Fingertip section 430 may also include one or moresensors, such as a pressure, positional, or tactile sensor, which mayprovide a control system with information about the position,orientation, and grip strength of the robotic finger.

IV. Example Robotic Hands

FIG. 5 illustrates an example robotic hand 500, according to an exampleimplementation. The example robotic hand may include a palm housing 510,and a plurality of robotic fingers 520A, 520B, and 520C, which may besimilar or identical to robotic finger 400. Robotic fingers 520A, 520B,and 520C may include treads or another grippable surface. In someexamples, robotic hand 500 may be connected to an arm, leg, or othercomponent of the quadruped robot 200 and/or biped robot 300, or one ormore other robotic devices and/or systems. Robotic hand 500 may includethree robotic fingers, as shown in FIG. 5, or may include two, four, orany other number of robotic fingers. In some examples, the roboticfingers are positioned on opposite sides of the robotic hand (as shownin FIG. 5), while in other examples the robotic fingers may bepositioned evenly around the perimeter of the robotic hand, or all oneside, or any other orientation. In addition, the robotic hand may take adifferent shape than shown.

FIG. 6 illustrates an example robotic hand 600, according to an exampleimplementation. Robotic hand 600 may include a palm housing 610, and aplurality of robotic fingers 640A, 640B, and 640C. Palm housing 610 maydefine a cavity 620, which may include one or more components of therobotic hand 600.

Cavity 620 may include a plurality of actuators 630A, 630B, and 630C.The plurality of actuators may function to control robotic fingers 640A,640B, and 640C such that the robotic fingers move to grasp an object.The plurality of actuators may be hydraulic actuators, electromechanicalactuators, or any other type of actuator. Each of the plurality ofactuators may be aligned perpendicular to a respective robotic finger,such that the act of actuating occurs in the plane of the palm housing,and generally perpendicular to the robotic fingers as shown. In someexamples the number of actuators may be the same as the number ofrobotic fingers. Alternatively, there may be two or more actuators thatcorrespond to each robotic finger. Other orientations and number ofhydraulic actuators are possible as well.

FIG. 7 illustrates an example robotic hand 700 having example roboticfingers 710A, 710B, and 710C, according to an example implementation.Robotic fingers 710A, 710B, and 710C may be similar or identical torobotic finger 400 in some respects. For instance, robotic finger 710Aincludes second member 711, a plurality of linkages 720A and 720B, and afingertip section 730, which may correspond to second member 411,plurality of linkages 420A and 420B, and fingertip section 430 ofrobotic finger 400. Second member 711 may include a plurality offlexible sections 712A and 712B, as well as a plurality of joints 714A,714B, and 714C, which may correspond to the plurality of flexiblesections 414A and 414B, and plurality of second joints 414A, 414B, and414C shown in FIG. 4.

Robotic finger 700 in FIG. 7 may include first member 701, which mayinclude a plurality of rigid sections 702A and 702B. As shown in FIG. 7,the plurality of rigid sections 702A and 702B may be arranged in astraight configuration, as opposed to a slightly curved orientation ofthe plurality of rigid sections 402A and 402B shown in FIG. 4. Further,the plurality of rigid sections 702A and 702B may cover one or morejoints (not shown) that connect the plurality of rigid sections.

In some examples, the first member 701 may include an elastomer sectionthat runs the length of the first member 701. The elastomer section maybe included in each rigid section of the first member 701, and the rigidsections 702A and 702B may act as an exoskeleton for the first member701. In this example, the first member 701 may bend and/or twist when aside load is imparted onto the side of first member 701, while remainingstiff when a load is imparted onto the gripping side of the finger.

FIG. 8 illustrates an example robotic hand 800 having example roboticfingers 810A, 810B, and 810C according to an example implementation.Robotic fingers 810A, 810B, and 810C may be similar or identical torobotic finger 400 in some respects. For instance, robotic finger 810Aincludes first member 801, second member 811, and a plurality oflinkages 820A, 820B, and 820C, which may correspond to first member 401,second member 411, and plurality of linkages 420A and 420B of roboticfinger 400.

First member 801 may include a plurality of rigid sections 802A, 802B,and 802C, and a plurality of first joints 804A, 804B, 804C, and 804D,which may be similar or identical to one or more of the plurality ofrigid sections 402A and 402B and plurality of first joints 404A, 404Band 404C described with reference to FIG. 4. Second member 811 mayinclude a plurality of flexible sections 812A, 812B, and 812C, connectedend-to-end by a plurality of second joints 814A, 814B, and 814C, whichmay be similar or identical to the plurality of flexible sections 412Aand 412B, and the plurality of second joints 414A, 414B, and/or 414C.

Robotic finger 800 may differ from one or more other robotic fingersdescribed herein in that it includes three rigid sections and threeflexible sections, as opposed to two as shown in FIGS. 4-7 and describedabove. In addition, the plurality of flexible sections in FIG. 8 mayinclude one or more grippable surfaces or treads that run parallel tothe length of the finger. The treads may include one or more ridgesand/or bumps that allow the finger to grip an object. In some cases, theplurality of flexible sections 812A, 812B and 812C may be a combinationof two or more materials. For instance, flexible sections 812A, 812B,and 812C may include a first material configured to have a strongability to grip an object, and a second material configured to bendeasily and return to an initial state when a pressure is applied andremoved. Other configurations are possible as well.

Further, robotic finger 810A may include a fingertip section 430 thatincludes rigid section 802C and flexible section 812C. In some examples,the fingertip section need not be a separate component of the roboticfinger, but may be a component including parts of the first member andthe second member. Fingertip section 830 may include a joint 804D, whichmay be similar or identical to other joints discussed herein.

V. Example Operations

FIG. 9 illustrates a flowchart of an example method 900 of operating arobotic finger according to an example implementation. This exampleapplies to a robotic finger comprising three sections, but may beapplied to a finger comprising a fewer or greater number of sections.The method 900 may be applied to any of the robotic fingers or handsdescribed in this disclosure, such as robotic finger 400, or robotichands 500, 600, 700, and/or 800. Further, method 900 may be carried outby the robotic system 100, quadruped robot 200 and/or biped robot 300.

At block 902, method 900 may include a robotic finger in an initialstate, not in contact with an object. The initial state may be a statesuch as those shown in and described with reference to FIGS. 4-8, or maybe another initial state. In some examples, the initial state of therobotic finger includes an open orientation, such that a hand having twoor more robotic fingers can attempt to grasp an object. The initialstate of the robotic finger may also be a state in which the pluralityof flexible sections are in a straight or nearly straight configuration.

A robotic system that includes one or more robotic fingers of thisapplication may attempt to grasp an object using the one or more roboticfingers. As such, the robotic system may move toward an object andposition the fingers such that they come into contact with the object.

At block 903, the method determines which section makes the first pointof contact with the object. The method may continue with block 904, 908,or 912 depending on which section makes the first contact.

At block 904, method 900 may include a first flexible section contactingthe object. In some examples the first flexible section is the flexiblesection furthest from the fingertip (i.e. closest to the palm). Thefirst flexible section may initially make contact at a single point, andresponsively flex, bend, or deform based on a force exerted by theobject. The first flexible section may deform such that additionalpoints of contact are made with the object. The additional points ofcontact may be made by the first flexible section wrapping around theobject, and conforming to the shape of the object.

At block 905, the method determines whether a stable grasp of the objecthas been achieved. Where a stable grasp has been achieved, the methodmay end. However, if a stable grasp has not yet been achieved, themethod may continue with block 906.

At block 906, method 900 may include the first flexible section bendingand pulling a second flexible section toward the object. When the firstflexible section deforms in response to the force exerted by the object,the deformation may pull the first flexible section out of its initialstate by pulling a joint connecting the first flexible section towardthe object. In response, the respective joint, second flexible section,and linkage connected to the first flexible section may be pulled out ofthe initial state as well. In effect, the first flexible section pullsthe second flexible section such that it curls or wraps around theobject.

At block 908, method 900 may include the second flexible sectioncontacting the object. As a result of the pull by the first flexiblesection, the second flexible section curling toward the object maycontact the object an initial point.

At block 909, the method determines whether a stable grasp of the objecthas been achieved. Where a stable grasp has been achieved, the methodmay end. However, if a stable grasp has not yet been achieved, themethod may continue with block 910.

Then, at block 910, method 900 may include the second flexible sectionbending, flexing, and/or deforming, which may create additional pointsof contact between the second flexible section and the object. As aresult of the second flexible section bending toward the object, arespective joint connecting the second flexible section and a fingertipsection may be pulled toward the object. The fingertip section may alsobe pulled toward the object. As a result, each flexible section may havemultiple points of contact with the object, which may allow for astronger and more stable grip.

At block 912, method 900 may include the fingertip section makingcontact with the object. The object thus has contact with the firstflexible section, the second flexible section, and the fingertipsection.

In some examples, the ratio of lengths of the first and second rigid andflexible sections is such that the robotic finger has an injectinggrasp. For instance, where the length of the first rigid and flexiblesections is longer than the second rigid and flexible sections, contactwith an object by the first flexible section and the resultingdeformation as described with reference to method 900 may cause theobject to be pulled inward toward the palm, as opposed to pushed out.

The effect of grasping an object with the disclosed robotic finger isthat there are increased points of contact as compared to purely rigidbody fingers having one or more articulable knuckles, while maintaininga strong grasp.

VI. Example Clutch and Coupling

FIGS. 10A, 10B, and 11 illustrate an example clutch and coupling thatmay be connected to the robotic finger described herein. The clutch maybe connected to a proximal end of the first member and a proximal end ofthe second member. The clutch may include a groove or surface with adetent. The coupling may be connected to the clutch, and may have one ormore components such that the coupling and the clutch maintain a linearrelationship when in a state of normal operation, while allowing theclutch and coupling to rotate out of the linear relationship when aforce applied to the side of the robotic finger is more than a thresholdforce.

FIG. 10A illustrates a cross-sectional view of an example clutch 1010and coupling 1020, according to an example implementation. The clutch1010 may be connected to a robotic finger 1000, which may be similar oridentical to the robotic finger 400 described herein with reference toFIG. 4.

The clutch 1010 may include a groove 1012, with a detent 1014. In thisexample, the groove runs in a generally straight line perpendicular to aplane including the robotic finger 1000. In other examples, the groovemay run in a different direction or may be oriented along a differentaxis. Further, the groove 1012 may have a different shape, such as astraight line, curve, bend, or any other shape. The groove 1012 may bein a central portion of the clutch 1010, as shown in FIG. 10A. In someexamples, the groove 1012 may be located off-center or toward a side ofthe clutch.

The coupling 1020 may include one or more components that act tomaintain a linear relationship between the clutch and the coupling. Inthe example shown in FIG. 10B, the components include a spring 1022 anda ball 1024. In other examples the coupling may include one or more pinsor other elements that can be used to arrest a rotation of the couplingwith respect to the clutch. The spring 1022 and ball 1024 may bepositioned in or on the coupling 1020 such that the ball is pressed intothe detent 1014. The ball resting in the detent may be a state ofequilibrium of the clutch and coupling system, such that a force isrequired to move the system out of that state.

The clutch and coupling may be rotatably connected (not shown), and inaddition, the spring 1022 and ball 1024 may be statically attached tothe coupling such that the coupling cannot move without the ball moving.Further, the ball may be positioned such that it can roll along thegroove when the clutch and coupling rotate with respect to each other.

In some implementations, there may be a force which acts upon a side ofa robotic finger coupled to the clutch. Where the force is more than athreshold force, the spring may compress and the ball may move out ofthe detent, allowing the clutch and coupling to rotate with respect toeach other. The strength of the spring, shape and size of the ball, andshape and size of the groove and detent may affect the threshold forceneeded to allow the clutch and coupling to rotate. In some examples, thethreshold force may be defined in terms of a torque acting on thefinger. For example, the force may be a force acting on the fingertipsection of the finger, and the threshold may be 1 N*m (Newton-meter). Inother examples, the dimensions and specifications of the components ofthe clutch and coupling may be selected such that a higher or lowerthreshold is required.

FIG. 10B illustrates a bottom view of the example clutch 1010, accordingto an example implementation. The clutch 1010 may include the groove1012 and the detent 1014 as shown in FIG. 10B. In some examples, thedetent 1014 may be positioned in the center of the groove 1012. This mayallow the clutch and coupling to align through a central axis when theball is in the detent. It may also allow the clutch to rotate in twodirections with respect to the coupling (i.e., such that the ball canroll on either side of the detent).

FIG. 11 illustrates a three-dimensional view of the example clutch 1010and coupling 1020, according to an example implementation.

The clutch 1010 may include the groove 1012 with the detent 1014. Inaddition the clutch 1010 may include a top face 1018 and a bottom face1016. The top face 1018 may be connected to a robotic finger, such asany of the robotic fingers described in this disclosure, includingrobotic finger 400. The bottom face 1016 of the clutch 1010 may becurved, such that it can rotate through an axis when a force acts uponthe finger and/or clutch.

The coupling 1020 may include the spring 1022 and ball 1024, as well asa top member 1026, a top face 1028, a bottom face 1030 and a side face1032. The top member 1026 may be positioned such that it fits into thegroove 1012, and allows the clutch and coupling to rotate. In someexamples, the top member 1026 may match the size and shape of the groove1012. In other examples, the top member 1026 may have a different shapeand size than the groove 1012. The top member 1026 and/or groove 1012may have a rectangular or square shape, or may be circular, ovoid,elliptical, or another shape.

The top member 1026 of the coupling 1020 may include the spring 1022 andball 1024. The spring 1022 and ball 1024 may be oriented such that theball rolls in the groove when the clutch and coupling rotate withrespect to each other. The groove 1012 and detent 1014 may also beconfigured such that rotation of the clutch and coupling is arrestedwhen the ball rolls into the detent. Further, the ball may only roll outof the detent when a force more than a threshold force is applied to aside of a finger connected to the top face 1018, or a side of the clutch1010.

In some examples, the top face 1028 of the coupling may be curved, suchthat it allows the clutch and coupling to rotate smoothly. The curve inthe top face 1028 of the coupling 1020 may match or correspond to acurve in the bottom face 1016 of the clutch 1010.

The coupling 1020 may also include a bottom face 1030 and a side face1032, either of which may be connected to a palm or hand of a roboticdevice. As such, the clutch 1010 and coupling 1020 may together bepositioned between a palm and finger of a robotic device, allowing thefinger to rotate perpendicular to a normal axis of movement (i.e.perpendicular to a gripping axis) when force greater than a thresholdforce acts upon the finger. This may allow the robotic hand to avoiddamage to the finger when a force acts upon the finger in anunanticipated or unintended direction. In some embodiments, theconfiguration of the clutch and coupling may be switched. In that casethe coupling may be connected to the finger, and the clutch connected tothe palm. The ball and spring may be included in the coupling that isconnected to the finger, and the ball may roll in a grove/detentincluded in the clutch connected to the palm.

VII. Conclusion

It should be understood that arrangements described herein are forpurposes of example only. As such, those skilled in the art willappreciate that other arrangements and other elements (e.g. machines,interfaces, operations, orders, and groupings of operations, etc.) canbe used instead, and some elements may be omitted altogether accordingto the desired results. Further, many of the elements that are describedare functional entities that may be implemented as discrete ordistributed components or in conjunction with other components, in anysuitable combination and location, or other structural elementsdescribed as independent structures may be combined.

While various aspects and implementations have been disclosed herein,other aspects and implementations will be apparent to those skilled inthe art. The various aspects and implementations disclosed herein arefor purposes of illustration and are not intended to be limiting, withthe true scope being indicated by the following claims, along with thefull scope of equivalents to which such claims are entitled. It is alsoto be understood that the terminology used herein is for the purpose ofdescribing particular implementations only, and is not intended to belimiting.

What is claimed is:
 1. A robotic finger comprising: a first memberhaving a plurality of rigid sections that are rotatably connectedend-to-end through respective first joints, wherein each first jointconnects two rigid sections such that the two rigid sections rotateabout the same axis; a second member comprising a single flexiblesection; a plurality of linkages connecting the first member and thesecond member so as to align the single flexible section with theplurality of rigid sections side-by-side, wherein a respective linkageconnects a respective first joint of the first member to a correspondingpoint of the second member; and a fingertip section that connects adistal end of the first member to a distal end of the second member,wherein the first member and the second member form a trapezoidal shape,such that the distal end of the first member and the distal end of thesecond member are closer to each other than a proximate end of the firstand second members.
 2. The robotic finger of claim 1, wherein theplurality of rigid sections consists of two rigid sections.
 3. Therobotic finger of claim 1, wherein the first member having the pluralityof rigid sections comprises a first rigid section and a second rigidsection, wherein the first rigid section is rotatably connected to thefingertip section and is shorter than the second rigid section.
 4. Therobotic finger of claim 1, wherein the plurality of rigid sectionscomprise plastic.
 5. The robotic finger of claim 1, wherein the singleflexible section comprises a first portion extending from a proximateend of the first member to a first linkage, and a second portionextending from the first linkage to the distal end of the first member,wherein the first portion is longer than the second portion.
 6. Therobotic finger of claim 1, wherein the single flexible section is anelastomer.
 7. The robotic finger of claim 1, wherein the plurality oflinkages connecting the first member and the second member comprises: aplurality of rigid linkages, wherein a first end of a respective linkageis rotatably connected to the respective first joint of the firstmember, and a second end of the respective linkage is rotatablyconnected to a corresponding second point of the second member.
 8. Therobotic finger of claim 1, wherein the plurality of linkages connectingthe first member and the second member comprises: a first linkageconnecting a proximate end of the first member to a proximate end of thesecond member; and a second linkage connecting a central part of thefirst member to a central part of the second member, wherein the secondlinkage is shorter than the first linkage.
 9. The robotic finger ofclaim 1, further comprising: a clutch connected to a proximal end of thefirst member and a proximal end of the second member, the clutch havinga groove with a detent; and a coupling connected to the clutch, whereinthe coupling maintains a linear relationship with the clutch when thefinger is in a state of normal operation, and allows the clutch andcoupling to rotate out of the linear relationship when a force appliedto a side of the robotic finger is more than a threshold force.
 10. Arobotic hand comprising: a palm housing defining a cavity; a pluralityof hydraulic actuators positioned in cavity; and a plurality of roboticfingers coupled to the hydraulic actuators, wherein each robotic fingercomprises: a first member having a plurality of rigid sections that arerotatably connected end-to-end through respective first joints, whereineach first joint connects two rigid sections such that the two rigidsections rotate about the same axis; a second member comprising a singleflexible section; a plurality of linkages connecting the first memberand the second member so as to align the single flexible section withthe plurality of rigid sections side-by-side, wherein a respectivelinkage connects a respective first joint of the first member to acorresponding point of the second member; and a fingertip section thatconnects a distal end of the first member to a distal end of the secondmember, wherein the first member and the second member form atrapezoidal shape, such that the distal end of the first member and thedistal end of the second member are closer to each other than aproximate end of the first and second members.
 11. The robotic hand ofclaim 10, wherein the plurality of rigid sections consists of two rigidsections.
 12. The robotic hand of claim 10, wherein the first memberhaving the plurality of rigid sections comprises a first rigid sectionand a second rigid section, wherein the first rigid section is rotatablyconnected to the fingertip section and is shorter than the second rigidsection.
 13. The robotic hand of claim 10, wherein the plurality ofrigid sections comprise plastic.
 14. The robotic hand of claim 10,wherein the single flexible section comprises a first portion extendingfrom a proximate end of the first member to a first linkage, and asecond portion extending from the first linkage to the distal end of thefirst member, wherein the first portion is longer than the secondportion.
 15. The robotic hand of claim 10, wherein the single flexiblesection is an elastomer.
 16. The robotic hand of claim 10, wherein theplurality of linkages connecting the first member and the second membercomprises: a plurality of rigid linkages, wherein a first end of arespective linkage is rotatably connected to the respective first jointof the first member, and a second end of the respective linkage isrotatably connected to the corresponding point of the second member. 17.The robotic hand of claim 10, wherein the plurality of linkagesconnecting the first member and the second member comprises: a firstlinkage connecting a proximate end of the first member to a proximateend of the second member; and a second linkage connecting a central partof the first member to a central part of the second member, wherein thesecond linkage is shorter than the first linkage.
 18. The robotic handof claim 10, each robotic finger further comprising: a clutch connectedto a proximal end of the first member and a proximal end of the secondmember, the clutch having a groove with a detent; and a couplingconnected to the clutch, wherein the coupling maintains a linearrelationship with the clutch when the finger is in a state of normaloperation, and allows the clutch and coupling to rotate out of thelinear relationship when a force applied to a side of the robotic fingeris more than a threshold force.